Italian multicenter, prospective study to evaluate the negative predictive value of 16- and 64-slice MDCT imaging in patients scheduled for coronary angiography (NIMISCAD-Non Invasive Multicenter Italian Study for Coronary Artery Disease)

This was a prospective, multicenter study designed to evaluate the utility of MDCT in the diagnosis of coronary artery disease (CAD) in patients scheduled for elective coronary angiography (CA) using different MDCT systems from different manufacturers. Twenty national sites prospectively enrolled 367 patients between July 2004 and June 2006. Computed tomography (CT) was performed using a standardized/optimized scan protocol for each type of MDCT system (≥16 slices) and compared with quantitative CA performed within 2 weeks of MDCT. A total of 284 patients (81%) were studied by 16-slice MDCT systems, while 66 patients (19%) by 64-slice MDCT scanners. The primary analysis was on-site/off-site evaluation of the negative predictive value (NPV) on a per-patient basis. Secondary analyses included on-site evaluation on a per-artery and per-segment basis. On-site evaluation included 327 patients (CAD prevalence 58%). NPV, positive predictive value (PPV), sensitivity, specificity, and diagnostic accuracy (DA) were 0.91 (95% CI 0.85–0.95), 0.91 (95% CI 0.86–0.95), 0.94 (95% CI 0.89–0.97), 0.88 (95% CI 0.81–0.93), and 0.91 (95% CI 0.88–0.94), respectively. Off-site analysis included 295 patients (CAD prevalence 56%). NPV, PPV, sensitivity, specificity, and DA were 0.73 (95% CI 0.65–0.79), 0.93 (95% CI 0.87–0.97), 0.73 (95% CI 0.65–0.79), 0.93 (95% CI 0.87–0.97), and 0.82 (95% CI 0.77–0.86), respectively. The results of this study demonstrate the utility of MDCT in excluding significant CAD even when conducted by centers with varying degrees of expertise and using different MDCT machines.     

Morphological MRI criteria improve the detection of lymph node metastases in head and neck squamous cell carcinoma: multivariate logistic regression analysis of MRI features of cervical lymph nodes

The aim was to evaluate whether morphological criteria in addition to the size criterion results in better diagnostic performance of MRI for the detection of cervical lymph node metastases in patients with head and neck squamous cell carcinoma (HNSCC). Two radiologists evaluated 44 consecutive patients in which lymph node characteristics were assessed with histopathological correlation as gold standard. Assessed criteria were the short axial diameter and morphological criteria such as border irregularity and homogeneity of signal intensity on T2-weighted and contrast-enhanced T1-weighted images. Multivariate logistic regression analysis was performed: diagnostic odds ratios (DOR) with 95% confidence intervals (95% CI) and areas under the curve (AUCs) of receiver-operating characteristic (ROC) curves were determined. Border irregularity and heterogeneity of signal intensity on T₂-weighted images showed significantly increased DORs. AUCs increased from 0.67 (95% CI: 0.61–0.73) using size only to 0.81 (95% CI: 0.75–0.87) using all four criteria for observer 1 and from 0.68 (95% CI: 0.62–0.74) to 0.96 (95% CI: 0.94–0.98) for observer 2 (p < 0.001). This study demonstrated that the morphological criteria border irregularity and heterogeneity of signal intensity on T2-weighted images in addition to size significantly improved the detection of cervical lymph nodes metastases.     

Spiral CT of pulmonary nodules: interobserver variation in assessment of lesion size

The aim of this study was to assess interobserver variability in size determination of pulmonary nodules at spiral CT. Twenty-three patients with known pulmonary nodules (diameter 2–40 mm, mean diameter 7 mm) underwent spiral chest CT (collimation 5 mm, pitch 1). Images were reconstructed at 3- and 5-mm intervals (RI). Hard copies were analyzed by two radiologists who recorded every nodule with regard to location, diagnostic confidence (“definite,”“probable”) and nodule size in increments of 1 mm with specific attention to correct classification into one of three size classes (≤ 5 mm, 6–10 mm, > 10 mm). Interobserver variability was determined with Pearson's correlation coefficient and k measure. Of a total of 286 nodules, 103 nodules were found accordingly by both readers at 3 mm RI, and 96 at 5 mm RI. There was a good correlation of measurements (in millimeters) between both readers (Pearson's correlation coefficient: 0.89–0.95). Interobserver variability in categories was good at both reconstruction intervals (k: 0.61 at 3 mm, 0.74 at 5 mm RI) and very good (0.81) at 5 mm RI when uncertain nodules were excluded. Spiral CT allows reproducible size determination of pulmonary nodules as shown by good interobserver agreement in exact size measurement and categorization into three size classes. Received: 2 September 1999; Revised: 24 January 2000; Accepted: 27 January 2000     

Three-dimensional CT pyelography for planning of percutaneous nephrostolithotomy: accuracy of stone measurement, stone depiction and pelvicalyceal reconstruction

Retrospective evaluation of computed tomographic (CT) pyelography before percutaneous nephrostolithotomy (PCNL). Twenty patients with renal calculi underwent CT pyelography using a dedicated protocol. Calculus size, uniformity of contrast excretion and accuracy of calculus and pelvicalyceal (PC) system reconstructions were scored and compared on axial and coronal maximum intensity projections (MIP) and volume reconstructions (VRmovie loops). After contrast medium administration, the size of calculi is accurate on axial images, but underestimated on coronal studies: mean 14.7 mm vs. 14.4 mm (axial) and 17.2 mm vs. 16.1 mm (coronal) for measurements before and after enhancement, respectively (p = 0.11 and 0.03). Uniform contrast medium excretion (median 228 HU; 95% CI 209–266 HU) was sufficiently lower than calculus density (median 845 HU; 95% CI 457-1,193 HU) for precise calculus and pelvicalyceal reconstructions in 87% and 85%, respectively. Coronal MIP scans were rated best for calculus depiction (mean score 2.68 vs. 2.50 and 2.41 for coronal, axial and VRs, respectively; p = 0.14) and VR studies best for PC anatomy (mean score 4.4 vs. 3.73 and 2.89 for VR, coronal and axial studies, respectively; p = <0.0001). Three-dimensional CT pyelography can accurately demonstrate calculus position and spatial relationships of the collecting system before PCNL.     

Improved tumour detection by gastrin receptor scintigraphy in patients with metastasised medullary thyroid carcinoma

Purpose Radiopeptide imaging is a valuable imaging method in the management of patients with neuroendocrine tumours (NET). To determine the clinical performance of gastrin receptor scintigraphy (GRS), it was compared with somatostatin receptor scintigraphy (SRS), computed tomography (CT) and ¹⁸F-FDG positron emission tomography (PET) in patients with metastasised/recurrent medullary thyroid carcinoma (MTC).Methods Twenty-seven consecutive patients underwent imaging with GRS, SRS (19 patients), CT and PET (26 patients). GRS and SRS were compared with respect to tumour detection and uptake. CT, PET, magnetic resonance imaging (MRI), ultrasound (US) and follow-up were used for verification of findings. In addition, GRS, CT and PET were directly compared with each other to determine which method performs best.Results Nineteen patients underwent both GRS and SRS. Among these, GRS showed a tumour detection rate of 94.2% as compared to 40.7% for SRS [mean number of tumour sites (±SD) and 95% confidence intervals (CI): GRS 4.3±3.1/2.8–5.7, SRS 1.8±1.6/1.1–2.6]. In 26 patients, GRS, CT and PET were compared. Here, GRS showed a tumour detection rate of 87.3% (CT 76.1%, PET 67.2%; mean number of tumour sites and 95% CI: GRS 4.5±4.0/2.9–6.1, CT 3.9±3.5/2.5–5.3, PET 3.5±3.3/2.1–4.8). If GRS and CT were combined, they were able to detect 96.7% of areas of tumour involvement.Conclusion GRS had a higher tumour detection rate than SRS and PET in our study. GRS in combination with CT was most effective in the detection of metastatic MTC.     

Diagnostic accuracy of in-stent coronary restenosis detection with multislice spiral computed tomography: a meta-analysis

This study was designed to define the current role of multislice spiral computed tomography (MSCT) for the diagnosis of coronary in-stent restenosis using a meta-analytic process. Restenosis remains a limitation after coronary stent implantation and contributes to a substantial number of coronary re-assessments by conventional invasive coronary angiography (CA). We identified 15 studies (807 patients) evaluating in-stent restenosis by means of both MSCT (≥16 slices) and conventional CA until February 2007. After data extraction the analysis was performed according to a random-effects model. The analysis pooled the results from 15 studies with a total of 1,175 stents. A substantial number of unassessable stents (13%) were excluded from the analysis underscoring the shortcomings of MSCT. With this major limitation the diagnostic performance of MSCT for in-stent restenosis detection can be summarized as follows: the sensitivity and specificity were 84% [95% confidence interval (CI) 77–89%] and 91% (95% CI 89–93%), respectively, with positive and negative likelihood ratios of 12.2 (95% CI 6.6–22.6) and 0.23 (95% CI 0.17–0.31), respectively, and with a diagnostic odds ratio of 67.9 (95% CI 34.4–134.1). MSCT has shortcomings difficult to overcome in daily practice for in-stent restenosis detection and continues to have moderately high sensitivity and specificity. The diagnostic role of this emerging technology as an alternative to CA for in-stent restenosis detection remains limited.     

Major prognostic impact of persistent microvascular obstruction as assessed by contrast-enhanced cardiac magnetic resonance in reperfused acute myocardial infarction

The aim of this study was to compare the prognostic significance of microvascular obstruction (MO) and persistent microvascular obstruction (PMO) as assessed by cardiac magnetic resonance (CMR) in patients with acute myocardial infarction (AMI). CMR was performed in 184 patients within the week following successfully reperfused first AMI. First-pass images were performed to evaluate extent of MO and late gadolinium-enhanced images to assess PMO and infarct size (IS). Major adverse cardiac events (MACE) were collected at 1-year follow-up. MO and PMO were found in 127 (69%) and 87 (47%) patients, respectively. By using univariate logistic regression analysis, high Global Registry of Acute Coronary Events (GRACE) risk score (odds ratio [OR] 95% confidence interval [CI]: 3.6 [1.8–7.4], p < 0.001), IS greater than 10% (OR [95% CI]: 2.7 [1.1–6.9], p = 0.036), left ventricular ejection fraction less than 40% (OR [95% CI]: 2.4 [1.1–5.2], p = 0.027), presence of MO (OR [95% CI]: 3.1 [1.3–7.3], p = 0.004) and presence of PMO (OR [95% CI]:10 [4.1–23.9], p < 0.001) were shown to be significantly associated with the outcome. By using multivariate analysis, presence of MO (OR [95% CI]: 2.5 [1.0–6.2], p = 0.045) or of PMO (OR [95% CI]: 8.7 [3.6–21.1], p < 0.001), associated with GRACE score, were predictors of MACE. Presence of microvascular obstruction and persistent microvascular obstruction is very common in AMI patients even after successful reperfusion and is associated with a dramatically higher risk of subsequent cardiovascular events, beyond established prognostic markers. Moreover, our data suggest that the prognostic impact of PMO might be superior to MO.     

Detection of ventricular shunt malfunction in the ED: relative utility of radiography,CT, and nuclear imaging

The study objective was to determine the relative diagnostic utility of the radiographic shunt series (SS), head computed tomography (CT), and nuclear imaging performed in our Emergency Department (ED) for evaluating ventricular shunt malfunction. We retrospectively reviewed medical records, head CT (if performed), and nuclear imaging (if performed) for all ED patients with suspected shunt malfunction from 2002 to 2007 who underwent plain film shunt evaluation (296 cases/186 individuals) to determine if surgical shunt revision was performed. Logistic regression analysis was applied. Four percent (12/296) of radiographic SS were abnormal. Only 0.3% (1/296) underwent surgical revision in the absence of an abnormal head CT or nuclear imaging. Eighteen percent (51/282) of head CT exams were positive and 19% (24/128) of nuclear imaging exams were positive for shunt malfunction. Twenty-three percent (67/296) underwent surgical shunt revisions. Statistical analysis demonstrated that SS evaluation was not significantly associated with surgical shunt revision (OR 0.92; 95% CI, 0.7–1.2; p = 0.47). Head CT demonstrated a significant association with surgical revision (OR 1.4; 95% CI, 1.2–1.5; p < 0.001), as did nuclear imaging (OR 1.4; 95% CI, 1.2–1.6; p < 0.001). Patients with suspected ventricular shunt malfunction frequently require surgical revision. Abnormal radiographic SS was not associated with progression to surgical shunt revision, whereas abnormal head CT and abnormal nuclear imaging were significantly associated with surgical revision. We conclude that radiographic SS in the ED is of low diagnostic utility and that patients with suspected shunt malfunction should instead initially undergo CT and/or nuclear imaging.     

Lumbosacral epidural lipomatosis: MRI grading

Lumbosacral epidural lipomatosis (LEL) is characterized by excessive deposition of epidural fat (EF). The purpose of our retrospective study was to quantify normal and pathologic amounts of EF in order to develop a reproducible MRI grading of LEL. In this study of 2528 patients (1095 men and 1433 women; age range 18–84 years, mean age 47.3 years) we performed a retrospective analysis of MRI exams. We obtained four linear measurements at the axial plane parallel and tangent to the superior end plate of S1 vertebral body: antero-posterior diameter of dural sac (A-Pd DuS), A-Pd of EF, located ventrally and dorsally to the DuS, and A-Pd of the spinal canal (Spi C). We calculated (a) DuS/EF index and (b) EF/Spi C index. We developed the following MRI grading of LEL: normal, grade 0: DuS/EF index ≥1.5, EF/Spi C index ≤40%; LEL grade I: DuS/EF index 1.49–1, EF/Spi C index 41–50% (mild EF overgrowth); LEL grade II: DuS/EF index 0.99–0.34, EF/Spi C index 51–74% (moderate EF overgrowth); LEL grade III: DuS/EF index ≤0.33, EF/Spi C index ≥75% (severe EF overgrowth). The MRI exams were evaluated independently by three readers. Intra- and interobserver reliabilities were obtained by calculating Kappa statistics. The MRI grading showed the following distribution: grade 0, 2003 patients (79.2%); LEL grade I, 308 patients (12.2%); LEL grade II, 165 patients (6.5%); and LEL grade III, 52 patients (2.1%). The kappa coefficients for intra- and interobserver agreement in a four-grade classification system were substantial to excellent: intraobserver, kappa range 0.79 [95% confidence interval (CI), 0.65–0.93] to 0.82 (95% CI, 0.70–0.95); interobserver, kappa range 0.76 (95% CI, 0.62–0.91) to 0.85 (95% CI, 0.73–0.97). In LEL grade I, there were no symptomatic cases due to fat hypertrophy. LEL grade II was symptomatic in only 24 cases (14.5%). In LEL grade III, all cases were symptomatic. A subgroup of 22 patients (42.3%) showed other substantial spinal pathologies (e.g., disk herniation). By means of simple reproducible measurements and indexes MRI grading enables a distinction between mild, moderate, and severe EF hypertrophy. Kappa statistics indicate that LEL can be reliably classified into a four-grade system by experienced observers.     

Radiologist experience and CT examination quality determine metastasis detection in patients with esophageal or gastric cardia cancer

We aimed to separate the influence of radiologist experience from that of CT quality in the evaluation of CT examinations of patients with esophageal or gastric cardia cancer. Two radiologists from referral centers (‘expert radiologists’) and six radiologists from regional non-referral centers (‘non-expert radiologists’) performed 240 evaluations of 72 CT examinations of patients diagnosed with esophageal or gastric cardia cancer between 1994 and 2003. We used conditional logistic regression analysis to calculate odds ratios (OR) for the likelihood of a correct diagnosis. Expert radiologists made a correct diagnosis of the presence or absence of distant metastases according to the gold standard almost three times more frequently (OR 2.9; 95% CI 1.4–6.3) than non-expert radiologists. For the subgroup of CT examinations showing distant metastases, a statistically significant correlation (OR 3.5; 95% CI 1.4–9.1) was found between CT quality as judged by the radiologists and a correct diagnosis. Both radiologist experience and quality of the CT examination play a role in the detection of distant metastases in esophageal or gastric cardia cancer patients. Therefore, we suggest that staging procedures for esophageal and gastric cardia cancer should preferably be performed in centers with technically advanced equipment and experienced radiologists.     

Percutaneous transluminal angioplasty of peripheral bypass stenoses

Purpose: To assess the success of percutaneous transluminal angioplasty (PTA) in treating peripheral bypass stenoses. Methods: Patients who received a femoropopliteal or femorocrural bypass graft for limb ischemia were included in a duplex surveillance program. If duplex ultrasound revealed a short (<2 cm) severe (peak systolic velocity ratio ≥ 4.5) stenosis, patients were scheduled for arteriography and PTA. Fifty-eight peripheral bypass stenoses in 39 grafts in 37 patients were treated with PTA. The cumulative primary patency of treated stenoses was calculated. Results: During the first year after PTA 31 (53%) treated lesions remained patent, 15 (26%) lesions restenosed at a median interval of 5.0 (range 1–12) months and 4 (7%) bypasses occluded. The cumulative primary patency of 58 treated graft stenoses at 1 year was 60% [95% confidence interval (CI) 46%–74%] and 55% (95% CI 41%–70%) at 2 years. Graft body stenoses showed a better 2-year cumulative primary patency (86%; 95% CI 68%–100%) compared with juxta-anastomotic lesions (45%; 95% CI 29%–62%; p < 0.05). Conclusion: PTA is justifiable as the initial treatment of peripheral bypass stenoses. Nevertheless, the restenosis rate is rather high, especially in juxta-anastomotic lesions. Continuation of duplex surveillance after PTA and timely reintervention is recommended.     

Can CT predict the source of arterial hemorrhage in patients with pelvic fractures?

The objective of the study was to evaluate the ability of hemorrhage site and location as demonstrated on pelvic CT to predict the source of arterial hemorrhage in patients with traumatic pelvic fractures. CT scans of 104 consecutive patients who had sustained traumatic pelvic fracture and undergone emergent pelvic angiography were digitized, and fracture-related hemorrhage area and volume were measured at multiple locations within the pelvis. Clots that measured greater than 10 cm² were compared to angiographic results. The χ² test was used to find locations on CT that were significantly associated with specific arterial injuries found on angiography. Sixty-one (58%) of the patients had arterial bleeding at angiography. The most commonly injured arteries were the internal pudendal and the superior gluteal. Specific locations on CT were statistically significant indicators of injury to the superior gluteal artery (relative risk=2.9, 95% CI 1.2–7.3, P=0.013), the anterior division of the internal iliac artery (relative risk=3.2, 95% CI 1.4–4.1, P=0.006), and the internal pudendal arteries (relative risk=2.0, 95% CI 1.1–4.0, P=0.037). More blood was visible on CT when an artery was injured (mean volume with negative angiogram=318 ml, mean volume with positive angiogram=554 ml, (P=0.007)). The rectus sheath region at the top of the iliac crest (P=0.004), pelvic sidewalls at the L5–S1 disk space level (P=0.001), and gluteal regions also at the L5–S1 disk space level (P=0.012) were significant indicators of a positive arteriogram. CT can help predict the specific bleeding artery to potentially guide angiographic intervention. Electronic Publication     

Combined FDG-PET/CT for the detection of unknown primary tumors: systematic review and meta-analysis

The aim of this study was to systematically review and meta-analyze published data on the diagnostic performance of combined 18F-fluoro-2-deoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) in the detection of primary tumors in patients with cancer of unknown primary (CUP). A systematic search for relevant studies was performed of the PubMed/MEDLINE and Embase databases. Methodological quality of the included studies was assessed. Reported detection rates, sensitivities and specificities were meta-analyzed. Subgroup analyses were performed if results of individual studies were heterogeneous. The 11 included studies, comprising a total sample size of 433 patients with CUP, had moderate methodological quality. Overall primary tumor detection rate, pooled sensitivity and specificity of FDG-PET/CT were 37%, 84% (95% CI 78–88%) and 84% (95% CI 78–89%), respectively. Sensitivity was heterogeneous across studies (P = 0.0001), whereas specificity was homogeneous across studies (P = 0.2114). Completeness of diagnostic workup before FDG-PET/CT, location of metastases of unknown primary, administration of CT contrast agents, type of FDG-PET/CT images evaluated and way of FDG-PET/CT review did not significantly influence diagnostic performance. In conclusion, FDG-PET/CT can be a useful method for unknown primary tumor detection. Future studies are required to prove the assumed advantage of FDG-PET/CT over FDG-PET alone and to further explore causes of heterogeneity.     

The association between component malalignment and post-operative pain following navigation-assisted total knee arthroplasty: results of a cohort/nested case–control study

Previous studies have noted an adverse relationship between implant malalignment during total knee arthroplasty (TKA) and post-operative pain. Although some evidence exists indicating that computer-assisted surgical navigation for TKA can improve the accuracy of component alignment, its impact on clinical outcomes is currently unknown. The dual goals of the present cohort/nested case–control study were to (1) compare self-reported responses to the Western Ontario-McMaster Osteoarthritis Index (WOMAC) questionnaire between computer-assisted TKA (123 patients) using the imageless PiGalileo navigation system and conventional TKA (207 patients) [cohort analysis], and (2) to investigate a potential association between malalignment and post-operative pain in 19 painful knees and 19 asymptomatic knees obtained from the cohort analysis using matched sampling [nested case–control study]. In the cohort analysis, a relevant but non-significant (P = 0.06) difference in the occurrence of chronic pain was observed between the navigated (12%) and conventional arms (20%). Median post-operative WOMAC pain score was 100 (range, 50–100) in the conventional group and 100 (range, 65–100) in the navigated group. However, the Mann–Whitney test revealed a significant difference in favor of the navigated group (P = 0.01). In the nested case–control analysis, radiological outcomes and computer tomography (CT) measurements of femoral rotation were compared between the groups. The CT rotation measurements yielded evidence of a relationship between post-operative pain and incorrect rotational alignment of the femoral component of more than 3° (OR: 7; 95% CI: 1.2–42; P = .033). In conclusion, there was no clinical benefit to computer-assisted navigation; however, a statistically significant relationship was observed between incorrect rotational alignment of the femoral component and symptoms of post-operative pain following TKA.     

Orientation of trabecular bone in human vertebrae assessed by MRI

The aim of the study was to assess the relative number of bone trabeculae in different orientations by using magnetic inhomogeneity measurements by MR imaging. Twelve defatted human vertebrae (L2–L4) were studied by MR imaging and CT. In the MR measurements the reversible transaxial decay rate, R2', was determined using the GESFIDE sequence. The relative contribution to R2' of bone trabeculae oriented along the x (R2'_x), y (R2'_y) and z (R2'_y) axes was assessed, by rotation of the specimen in the magnetic field. The results were validated by CT measurements of trabecular structure at a resolution of 0.2 × 0.2 × 1 mm, using custom-made software. R2' ranged from 4.9 to 32 s^–1. After separation, theoretical R2'_x ranged from 2.3 to 10.7 s^–1, R2'_y ranged from 2.6 to 14.0 s^–1 and R2'_z ranged from 4.7 to 17.9 s^–1. The number of bone trabeculae per millimeter identified in axial CT images ranged from 0.15 to 0.38 and from 0.039 to 0.22 per millimeter in sagittal images. The difference between axial and sagittal CT images was statistically significant and due to anisotropic voxels. The correlation between R2' and the number of bone trabeculae per millimeter was statistically significant (r = 0.83, p < 0.001 for x orientation; r = 0.63 for y orientation, and r = 0.59 for z orientation, p < 0.05 for both). The relative amount of bone trabeculae in different orientations can be assessed in vitro using R2' measurements. Received: 10 April 1998; Revision received: 3 August 1998; Accepted: 5 August 1998     

Measurement of coronary calcium scores by electron beam computed tomography or exercise testing as initial diagnostic tool in low-risk patients with suspected coronary artery disease

We determined the efficiency of a screening protocol based on coronary calcium scores (CCS) compared with exercise testing in patients with suspected coronary artery disease (CAD), a normal ECG and troponin levels. Three-hundred-and-four patients were enrolled in a screening protocol including CCS by electron beam computed tomography (Agatston score), and exercise testing. Decision-making was based on CCS. When CCS≥400, coronary angiography (CAG) was recommended. When CCS<10, patients were discharged. Exercise tests were graded as positive, negative or nondiagnostic. The combined endpoint was defined as coronary event or obstructive CAD at CAG. During 12±4 months, CCS≥400, 10–399 and <10 were found in 42, 103 and 159 patients and the combined endpoint occurred in 24 (57%), 14 (14%) and 0 patients (0%), respectively. In 22 patients (7%), myocardial perfusion scintigraphy was performed instead of exercise testing due to the inability to perform an exercise test. A positive, nondiagnostic and negative exercise test result was found in 37, 76 and 191 patients, and the combined endpoint occurred in 11 (30%), 15 (20%) and 12 patients (6%), respectively. Receiver-operator characteristics analysis showed that the area under the curve of 0.89 (95% CI: 0.85–0.93) for CCS was superior to 0.69 (95% CI: 0.61–0.78) for exercise testing (P<0.0001). In conclusion, measurement of CCS is an appropriate initial screening test in a well-defined low-risk population with suspected CAD.     

Intraobserver and interobserver agreement of the interpretation of pediatric chest radiographs

The objective of this study is to quantify the magnitude of intraobserver and interobserver agreement among physicians for the interpretation of pneumonia on pediatric chest radiographs. Chest radiographs that produced discordant interpretations between the emergency physician and the radiologist's final interpretation were identified for patients aged 1–4 years. From 24 radiographs, eight were randomly selected as study radiographs, and 16 were diversion films. Study participants included two pediatric radiologists, two senior emergency medicine physicians, and two junior fellowship-trained pediatric emergency medicine physicians. Each test included 12 radiographs: the eight study radiographs and four randomly interspersed diversion radiographs, and each radiograph was paired with a written clinical vignette. Testing was repeated on four occasions, separated by ≥2 weeks. The dependent variable was the interpretation of presence or absence of pneumonia; primary analysis done with Cohen's kappa (95% confidence intervals). Intraobserver agreement was good for pediatric radiologists (kappa = 0.87; 95% CI 0.60–0.99) for both but was lower for senior emergency physicians (mean kappa = 0.68; 95% CI 0.40–0.95) and junior pediatric emergency physicians (mean kappa = 0.62; 95% CI 0.35–0.98). Interobserver agreement was fair to moderate overall; between pediatric radiologists, kappa = 0.51 (0.39–0.64); between senior emergency physicians, kappa = 0.55 (0.41–69), and between junior pediatric emergency medicine physicians, kappa = 0.37 (0.25–0.51). Practicing emergency clinicians demonstrate considerable intraobserver and interobserver variability in the interpretation of pneumonia on pediatric chest radiographs.     

Diffusion-weighted MR imaging in transient ischaemic attacks

The purpose of this study was to determine frequency and the characteristics of diffusion-weighted imaging (DWI) abnormalities in patients with transient ischaemic attack (TIA). We analysed data of 98 consecutive patients (mean age: 60.6±15.4 years, 56 men) admitted between January 2003 and April 2004 for TIA. Age, gender, symptom type and duration, delay from onset to magnetic resonance imaging (MRI), probable or possible TIA and cause of TIA were compared in patients with (DWI+) and without (DWI−) lesions on DWI. Volume and apparent diffusion coefficient (ADC) values of DWI lesions were computed. DWI revealed ischaemic lesions in 34 patients (34.7%). Lesions were small (mean volume: 1.9 cm³±3.3), and ADC was moderately decreased (mean ADC ratio: 79.5%). The diagnosis of TIA was considered as probable in all DWI+ patients. A multiple logistic regression model demonstrated that TIA duration greater than or equal to 60 min (OR, 7.6; 95% CI, 2.3–25.7), aphasia (OR, 9.2; 95% CI, 2.7–31.4) and motor deficit (OR, 5.1; 95% CI, 1.5–17.8) were independent predictors of DWI lesions. Prolonged TIA duration, aphasia and motor deficits are associated with DWI lesions. More than half of TIA patients with symptoms lasting more than 60 min have DWI lesions.     

Can perfusion CT assessment of primary colorectal adenocarcinoma blood flow at staging predict for subsequent metastatic disease? A pilot study

We aimed to determine whether perfusion CT measurements at colorectal cancer staging may predict for subsequent metastatic relapse. Fifty two prospective patients underwent perfusion CT at staging to estimate tumour blood flow, blood volume, mean transit time, and permeability surface area product. Patients considered metastasis free and suitable for surgery underwent curative resection subsequently. At final analysis, a median of 48.6 months post-surgery, patients were divided into those who remained disease free, and those with subsequent metastases. Vascular parameters for these two groups were compared using t-testing, and receiver operator curve analysis was performed to determine the sensitivity and specificity of these vascular parameters for predicting metastases. Thirty seven (71%) patients underwent curative surgery; data were available for 35: 26 (74%) remained disease free; 9 (26%) recurred (8 metastatic, 1 local). Tumour blood flow differed significantly between disease-free and metastatic patients (76.0 versus 45.7 ml/min/100 g tissue; p = 0.008). With blood flow <64 ml/min/100 g tissue, sensitivity and specificity (95% CI) for development of metastases were 100% (60–100%) and 73% (53–87%), respectively. Our preliminary findings suggest that primary tumour blood flow might potentially be a useful predictor warranting further study.